Windham Apts
Multifamily Housing in Seattle, WA · 420 BLANCHARD ST · 98121
At a glance
Windham Apts is a 37,300-square-foot multifamily housing building at 420 BLANCHARD ST in Seattle, Washington, built in 1925. In its 2025 Seattle benchmarking disclosure it reported an ENERGY STAR score of 72 out of 100 (grade B), a site energy-use intensity of 48.5 kBtu/ft² and 38 tCO₂e of greenhouse-gas emissions. That score is higher than 20% of the 1,652 scored multifamily housing buildings in Seattle.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 72 (band B) |
| Site EUI | 48.5 kBtu/ft² |
| Source EUI | 108.1 kBtu/ft² |
| GHG emissions | 38 tCO₂e |
| GHG intensity | 1.0 kgCO₂e/ft² |
| Electricity | 357,332 kWh |
| Natural gas | 5,899 therms |
| Gross floor area | 37,300 sq ft |
| Source record | seattle:19915:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | 72 | 48.5 kBtu/ft² | 38 tCO₂e | |
| 2024 | — | — | — | |
| 2023 | — | — | 31 tCO₂e | |
| 2022 | 57 | -10 | 53.9 kBtu/ft² | 39 tCO₂e |
| 2021 | 67 | +2 | 50.2 kBtu/ft² | 37 tCO₂e |
| 2020 | 65 | +19 | 50.4 kBtu/ft² | 40 tCO₂e |
| 2019 | 46 | -1 | 65.9 kBtu/ft² | 41 tCO₂e |
| 2018 | 47 | 63.2 kBtu/ft² | 39 tCO₂e | |
| 2017 | — | 68.3 kBtu/ft² | 42 tCO₂e | |
| 2016 | 46 | -9 | 48.5 kBtu/ft² | 43 tCO₂e |
| 2015 | 55 | 46.0 kBtu/ft² | 41 tCO₂e |
Compliance context
Seattle Energy Benchmarking Ordinance (SMC 22.920)
Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
Ownership
No owning organisation shown. Names of private individuals in the disclosure are not published here.
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Location
- Address
- 420 BLANCHARD ST
- City
- Seattle
- State
- Washington
- ZIP
- 98121
- Coordinates
- 47.61513, -122.34223
Within ~1 km
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How does Windham Apts compare with other multifamily housing buildings in Seattle?
The latest disclosures cover 1,971 multifamily housing buildings in Seattle, out of 3,871 buildings citywide. Windham Apts's ENERGY STAR score of 72 compares with an average of 83 across the 1,652 that report a score; it scores higher than 20% of them and lower than 79%. Its site EUI of 48.5 kBtu/ft² is about 39% above the average of 34.9 kBtu/ft² — it uses more energy per square foot than the typical building in that group. Its emissions intensity of 1.0 kgCO₂e/ft² is about 46% above the group average of 0.7 kgCO₂e/ft².
At 37,300 sq ft, it is about 57% below the average floor area of 86,468 sq ft for those buildings. It was built in 1925, 58 years earlier than the group's average year built (1983). Across all 24 jurisdictions BuildingCensus covers, the 59,945 multifamily housing buildings average an ENERGY STAR score of 70 and a site EUI of 59.0 kBtu/ft².
How has Windham Apts's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for Windham Apts, covering report years 2015–2025. Its ENERGY STAR score went from 55 in 2015 to 72 in 2025 (+17 points). Site EUI moved from 46.0 kBtu/ft² (2015) to 48.5 kBtu/ft² (2025), an 5% increase. Reported emissions went from 41 tCO₂e to 38 tCO₂e over the same span (down 7%).
What does an ENERGY STAR score of 72 mean?
ENERGY STAR scores run from 1 to 100 and are computed by the EPA's Portfolio Manager as a percentile against similar buildings nationwide, adjusted for climate, size and use: a score of 72 means the building performs better than about 72% of its national peers. BuildingCensus bands the score into report-card grades; 72 falls in band B — above median (70–84). It sits 3 points below 75, the threshold for ENERGY STAR certification. In Seattle, 69% of scored buildings are at 75 or above.
Site energy-use intensity (EUI) is the energy a building uses on site in a year divided by its floor area, in thousand Btu per square foot — lower is more efficient. Windham Apts's 48.5 kBtu/ft² across 37,300 sq ft works out to about 1.8 billion Btu (530 MWh-equivalent) in 2025. Its source EUI of 108.1 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 357,332 kWh of electricity and 5,899 therms of natural gas for the year.
Which law requires Windham Apts to report its energy use?
Windham Apts reports under the Seattle Energy Benchmarking Ordinance (SMC 22.920), the legal basis of Seattle's Building Energy Benchmarking program, which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2025 disclosure (source record seattle:19915:2025). Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
More multifamily housing buildings in Seattle
- Violett Apts On Melrose· 37,151 sq ft · score 100 (A)
- Maple Leaf Court· 37,091 sq ft · score 93 (A)
- Blue Heron Condominium· 37,090 sq ft · score 69 (C)
- Magnolian Apts· 37,086 sq ft · score 85 (A)
- The Crestview· 37,080 sq ft · score 71 (B)
- Strada 67 Apts· 36,992 sq ft · EUI 19.7 kBtu/ft²
- Multifamily Housing buildings in Seattle· 1,971 benchmarked
- All Seattle benchmarked buildings· Seattle Energy Benchmarking Ordinance (SMC 22.920)
- Most efficient large buildings in Seattle
- Least efficient large buildings in Seattle
- Biggest emitters in Seattle
Frequently asked questions
What is Windham Apts's energy grade?
Windham Apts scores 72 out of 100 on ENERGY STAR — band B, above median (70–84) — in its 2025 Seattle disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does Windham Apts use?
Its 2025 site energy-use intensity was 48.5 kBtu/ft² (108.1 kBtu/ft² source) across 37,300 sq ft, including 357,332 kWh of electricity and 5,899 therms of natural gas.
What are Windham Apts's carbon emissions?
Windham Apts reported 38 tCO₂e of greenhouse-gas emissions (1.0 kgCO₂e/ft²) for 2025.
Where is Windham Apts?
Windham Apts is at 420 BLANCHARD ST, in Seattle, Washington 98121. Its coordinates are 47.61513, -122.34223 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Windham Apts and when was it built?
Windham Apts has 37,300 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 1925 as its year built. It is classed as multifamily housing.
Is Windham Apts covered by the Seattle Energy Benchmarking Ordinance (SMC 22.920)?
Yes — it appears in the 2025 Building Energy Benchmarking disclosure, which lists the buildings reporting under the Seattle Energy Benchmarking Ordinance (SMC 22.920).
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About this data
Source: Building Energy Benchmarking (Seattle Energy Benchmarking Ordinance (SMC 22.920)), as published October 2, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “Windham Apts, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/windham-apts-554acbbc (data as of October 2, 2026).